This is about an old article posted in MSDN Magazine but I want to make sure you didn't miss the paragraphs about System.Transactions that Don put together in "A Guide to Developing and Running Connected Systems with Indigo":
“Indigo also provides significant support for transactional programming. Indigo-enabled versions of Windows support a service-based transaction manager that may be accessed via the System.Transactions framework or the WS-AtomicTransactions protocol. The new System.Transactions framework makes transactional programming simple and efficient throughout the platform (it supports SQL Server™, ADO.NET, MSMQ, distributed transaction coordinator (DTC), etc). System.Transactions supports both an explicit programming model based on the ITransaction interface as well as an implicit programming model in which transactions are automatically managed by Indigo. Both models are available to Indigo-based apps.
System.Transactions provides a new in-memory transaction manager that allows volatile transactions (that is, transactions that do not involve durable resources) to commit or roll back efficiently without incurring any disk I/O. To support durability, the in-memory transaction manager will transparently promote volatile transactions to durable transactions by coordinating through a disk-based transaction manager like the DTC the moment a durable resource manager enlists itself with a transaction.
System.Transactions defines a simple managed interface for writing both volatile and durable resource managers. System.Transactions also supports any resource manager that can speak either OLE transactions or the broadly adopted WS-AtomicTransaction protocol. To enable efficient transacted access to the file system, the Longhorn version of System.Transactions directly supports both the Kernel Transaction Manager (KTM) and the Transactional NTFS (TxNTFS).”